Contact-finger.



'- Patnted May 9, 1911.

H. A. STERN.

I OONTAVGT FINGER. APPLICATION Hum 91m. 6, 1910.

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UNITED STATES PATENT OFFIEE.

HALFDAN A. STEEN, OF MILWAUKEE, WISCONSIN, ASSIGNOR T0 ALLIS CHA LMERIS COMPANY, A CORPORATION OF NEW JERSEY.

CONTACT-FINGER.

Specification of Letters Patent.

Patented May 9, 1911.

Applicati'oifi'fled September 6, 1910. Serial m. 580,533.

new and useful Improvements in Contact-' Fingers, of which the following is a full, clear, and exact specification.

This invention relates to improvements in adjustable contact fingers to use in motor controllers, reversing switches. and similar electrical governing devices.

In contact fingers commonly used, it is necessary to make provision for adjusting them relatively to their cooperating, contact members for the reason that on account of slight irregularities in the cast and machined parts and the requirements of a support of some insulating material no two fingers would otherwise receive the same alinement. It is evident that where the fingers are resilient and are spring pressed, as they must necessarily be in order to secure (lose and eflicient'contact, any change in the alinement of a finger produces a variation in the pressure, with which the finger bears against its cooperating member, a deflection from the normal in one direction producing too heavy a pressure and consequently too much friction and wear between the parts, and a deflection in the opposite direction resulting, if in any contact at all, in too light a pressure between the parts and a bad contact. Adjustability is also desirable to compensate for wear which takes place during service in order that the predetermined pressure between contacts may be maintaincd. It is furthermore desirable to have aplurality of means for adjusting the contact finger, one for setting the contact in the proper position relative to its cooperative contact surface, and another for regulating the pressure between the contactmembers.

The object of this invention is to provide a simple, inexpensive contact finger, the parts of which may be adjusted readily to meet all requirements for efficient and successful operation. p

The various novel features of my invention will be described in the specification and particularly set forth in the appended claims. \i

This invention is illustrated on the accompanying sheet of drawin I o I c Flgure 1 1s a side elevation of mv 1min which 7 proved ontact finger in operative engagement with its cooperative contact surface, and F 2 is a front elevation of the same.

This. contact finger comprises a base or main "support 10 having preferably an integral projection '11 substantially at right angles to the body portion 12 of the base. The base 10. which is secured to any suitable insulating supporting member 13 by screws 14, is provided with an opening 15 for the reception of a pressure plate 16 to which the contact member 17 is connected. The contact member preferably comprises strips of steel 18, and copper'19 secured to a copper contact tip 20, the latter of which engages or is adapted to engage a cooperating contact surface 22. Dowel pins 21 driven into the Up 20 and projecting through holes 1n 'themetal strips 18 and 19 prevent the tip from turning about a screw 29.

The pressure plate l6 which receives the metallic strips 18 and 19 is provided with a V-shaped portion 23. which engages a 0061)- erating projection 24: of the walls 25 in the base 10. The projection 24 forms a fulcrum change the inclination of the contact memso ber 17 with respect to its support, thereby varying the pressure of the contact tip 21) on its cooperative contact surface 22.

Secured to the projection '11 of the support 10 is a strip of metal 27, preferably steel, forming a stiff spring. The free end of this spring is provided with a slot 28 for the reception of the screw 29, which passes through the metallic strips 18 and 19 into the contact tip 20, and which is held in a fixed position by alock-nut 30. The relative positions of the-contact finger and its cooperating cont-act member and the distance between the spring 27 and the projec- 7 surface 22. This adjustment is accomplishedQhy the use of the'screw 31. The desired pressure between the contact tip and its cooperative contact surface 22 is re'gulated 1 by thescrew-26, the end of which is rounded 1 'nd fits in a hollowed sure plate 16.

portion 32 of. the pres All of the parts of the base or support arepreferably formed integrally. One endof ,ustructe dthat the parts may be readily,as'-

lated. a It is evident-that thpre may be maxiy modi; fications of the'precise form and arran e- 2 5, 'meut tgerein show-n and'described and I aim the base or support is provided with an" opening33- for the reception of an electric conductor, which maybe secured therein by a screw 34.; This contact finger is-"so consembled', taken apart, or adjusted without any difliculty, whatever. 'And further, it iprov'i'des novel means whereby the con-tact member may be properly adjusted relative to its-cooperative contact surface and also means whereby the pressure between said contact member in my: claims -to.cover, allsuchmodifications iwhich do" not involve a departure. from the LEA contactfinger embodying a resilient for varying the distance between said spring and said support, and means for changing the .inclination of i said a contact member with mspectto'said' support.

Z Acontactffinger embodying the contact *membem'a. support therefor; a spring connected to -said support andgoperatively connected"w1th said contact member, and a pluralityfof members forchanging the inclination of saidcontact member with re-, spect to saidsupport. f-

v er..embodying a contactmember, a support therefor, a, spring: 0011- 3. A contact fi nected' to said support, and .operatively con- I .nected with sid contact member, and a plurality of adjusting' members for chang-' ing the inclination of said contact member and surface may. 'beregu with respect to said support all of said adjusting members engaging said support and one engaging said spring. w I

4. 'A contact finger embodying a reslhent contact member, a: support therefor, said contact member being adjustable about said support and pivotally arranged therewith, a

spring secured .to said support and operatively'connected with said contact member, and a plurality of means for changing the inclination of said cont-act member with. respect to the support.

5.. A contact finger having a contact member adapted to be pressed against a coiiperating contact surface, a support, a

spring secured to said support, means engaging said spring for adjusting the position of said contact member relative to said con-tact surface, and means for varying the pressure {of said contact member onsaid contact surface.

:6. In combination, a contactsurface, a contact finger having a contact member adapted to engage-said contact surface, a

support part of which forms a 'fulcrumfor said contact member, a. spring secured to said support and operatively connected with said contact member, means engaging said spring for adjusting the position of said contact member relative to said cooperating contact surface, and means for varying the. pressure of said contact finger, on said contact surface.- 4

"7. A contact finger-havinga-contact mem-.

ber adaptedto be pressed against a co-- operating contact surface, a support, a member connected to said support, means engaging said memberfor adjusting the position of said contact me'mber relative to said contact surface, and means engaging said support for varying the pressure of said contact member on said contact surface. Milwaukee, Wisconsin, August 26, 1910.- In testimony whereof I aifix my signature,

in the presence of two witnesses.

HALFDAN A. STEEN.

Witnesses: v

CHAS. L. BYRON, BOB. E. SToLn.

:Qoizics ot'this patent may beobtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. 0. 

